1. Field of the Invention
The invention disclosed in this specification and the like relates to a storage device and a driving method of the storage device.
2. Description of the Related Art
As one kind of volatile memories, a dynamic random access memory (DRAM) is widely known.
Meanwhile, in recent years, a metal oxide having semiconductor characteristics (hereinafter referred to as an oxide semiconductor) has attracted attention. An oxide semiconductor can be used for a transistor (see Patent Documents 1 and 2).
[Reference]
    [Patent Document 1] Japanese Published Patent Application No. 2007-123861    [Patent Document 2] Japanese Published Patent Application No. 2007-096055